Acute effects of RV pacingon cardiac hemodynamicsand transvalvular impedance

M.Taborsky, M.Fedorco, T.Skala, E.Kocianova, D.Richter, D.Marek, J.Ostransky

Dept. of Internal Medicine - Cardiology, University Hospital, Olomouc, Czech Republic

Chronic right-ventricular apical pacing can affect the cardiac function

Electrical and mechanical desynchronization

Reduced myocardial performance with increased stress

Increased risk of AF and CHF

Open questions

Does right-ventricular pacing (RVP) also produce acute effects on cardiac hemodynamics ?

Can the RVP long-term consequences be predicted from the acute effects ?

What are the most sensitive indicators of pacing-induced hemodynamic troubles ?

Is the hemodynamic impact of RVP dependent on the pacing site ?

Can the risk be reduced by individual pacing site selection ?

Study design During dual-chamber implantation procedures for SSS or

AVB, the ventricular lead was sequentially positioned in RV apex and mid-septum.

Measurements: left-ventricular pressure and dP/dt; systolic and diastolic hemodynamic parameters assessed by

2D echocardiography and by echo and tissue Doppler; Transvalvular impedance (TVI).

Recording conditions: intrinsic activity; AAI pacing at 90 bpm; VDD and DDD pacing at 90 bpm with apical and septal

stimulation.

AEGM

VEGM

ECG I

LVP

dP/dt

TVI(Vring)

150 mmHg

2000 mmHg/s

50 Ohm

Set of tracings

QRS duration

0

5

10

15

20

25 50 75 100 125 150 175 200 225 250

ms

fre

qu

en

cy (

n)

IAVC

VDD in RVA

VDD in RVS

QRS duration

0

50

100

150

200

ms

IAVC

VDD in RVA

VDD in RVS

P < 0.001

Paired Student t-test (n=29)

The increase in QRS duration induced by ventricular pacing depends on the pacing site

Paired Student t-test (n=29)

QRS duration difference vs IAVC

0

5

10

15

20

-25 0 25 50 75 100 125 150

ms

fre

qu

en

cy (

n)

VDD in RVA

VDD in RVS

QRS duration difference vs IAVC

0

25

50

75

100

ms

VDD in RVA

VDD in RVS

P < 0.001

The increase in QRS duration induced by ventricular pacing depends on the pacing site

AEGM

VEGM

ECG II

LVP

2:1 AVBQRS 110 ms

VDD in RVAQRS 180 ms

VDD in RVSQRS 120 ms

RV septal stimulation improves QRS axis and duration with respect to apical pacing

IAVC VDD; 80 ms AV delay

ECG I

LVP

dP/dt

dP/dt max

0

500

1000

1500

2000

Apex Septum

Pacing site

mm

Hg

/s

IAVC

VDD

P < 0.002 P < 0.005

dP/dtmax is reduced by RV pacing at either site

dP/dt max % diff. (VDD vs IAVC)

-20

-10

0

10

-20 -10 0 10

apex

sep

tum

Septal pacingwas better

Apical pacingwas better

y = x

Was there individual preference for a specific pacing site?

ECG II

LVP

dP/dt

IAVC VDD; 80 ms AV delay

LVP decrese in 50 ms

-100

-75

-50

-25

0

Apex Septum

Pacing site

mm

Hg

IAVC

VDD

P < 0.02 P < 0.01

LVP decrease is affected

LVP sys

0

50

100

150

200

Apex Septum

Pacing site

mm

Hg

IAVC

VDD

n.s. n.s.

LVP dias

0

2.5

5

7.5

10

Apex Septum

Pacing site

mm

Hg

IAVC

VDD

P < 0.001 P < 0.002

LVP sysis not modifiedby VDD pacing

LVP diasis significantlyincreased

Rate increase to 90 bpm produced by:

AAI pacing

DDD pacing (80 ms AV delay) in RV apex

DDD pacing (80 ms AV delay) in mid-septum

Effects of cardiac rate on dP/dtmax and LVP sys

dP/dt max

-10

0

10

20

30

40

AAI DDD apex DDD septum

ch

an

ge

vs

sin

us

ra

te (

%)

P < 0.001

n.s.

P < 0.002

LVP sys

-30

-20

-10

0

10

AAI DDD apex DDD septum

ch

an

ge

vs

sin

us

ra

te (

mm

Hg

)

P < 0.05

n.s. n.s.

Effects of RV pacing on echocardiographicsystolic parameters

EF

0

20

40

60

80

IAVC VDD apex VDD septum

(%)

n.s. n.s.

Mitral annulus systolic velocity

0

4

8

12

IAVC VDD apex VDD septum

(cm

/s)

n.s. n.s.

E'

0

4

8

12

IAVC VDD apex VDDseptum

(cm

/s)

P < 0.02 n.s.

E

0

25

50

75

100

IAVC VDD apex VDDseptum

(cm

/s)

n.s.n.s.

DT

0

100

200

300

IAVC VDD apex VDDseptum

(ms

)

P < 0.02n.s.

E/E'

0

10

20

30

IAVC VDD apex VDDseptum

n.s.n.s.

Echocardiographic diastolic parameters

RV lead in mid septum

AAI60 bpm

DDD60 bpm

TVI

VEGM

AEGM

ECG II

LVP

60 Ohm

100 mmHg

TVI

In some cases, RV pacing induced virtually no change in TVI waveform

AEGM

VEGM

ECG I

TVI

Sinusrhythm

VDD

EDTVI 421 Ohm

ESTVI 460 Ohm

EDTVI 434 Ohm

ESTVI 461 Ohm

RV lead in mid septum

TVI

In some cases, RV pacing affected TVI amplitude

transition from AAI to VDD

AEGM

VEGM

I

TVI 60 Ohm

LVP

RV lead in apex

In other cases, RV pacing induced morphological changes in TVI

TVI with intrinsic activity

0

5

10

15

20

25

30

35

apex septum

fre

qu

en

cy (

n)

inappropriate

appropriate

TVI with intrinsic activity

0

5

10

15

20

25

30

Y/Y Y/N N/Y N/N

waveform OK in apex / septum

fre

qu

en

cy (

n) P = 0.371

McNemar's test

TVI was measured in both RV apex and septum in 32 patients.The success frequency was not significantly differentat the two recording sites.

TVI recording can be performed in RV septum as well as in apex

TVI modifications in VDD

0

20

40

60

80

100

OK ampl. <75% altered morphology

fre

qu

en

cy (

%)

Apex

Septum

The frequency of substantial morphological alterationswas much higher in RV apex than septum

Right ventricular pacing affects TVI properties

TVI in VDD

0

5

10

15

20

Y/Y Y/N N/Y N/N

waveform OK in apex / septum

fre

qu

en

cy (

n)

P = 0.008McNemar's test

TVI in VDD

0

5

10

15

20

Y/Y Y/N N/Y N/N

waveform OK in apex / septum

fre

qu

en

cy (

n)

P = 0.016McNemar's test

OK = no morphological alteration OK = no morphological alterationand amplitude 75%

With intrinsic rhythm, the TVI signal was appropriate at both RV apex and septum in 25 cases.

The frequency of cases featuring unaltered TVI waveform with VDD pacing was significantly higher in RV septum than apex.

OK = no morphological alteration OK = no morphological alterationand amplitude 75%

DDD was tested in 18 cases featuring appropriate TVI at both RV apex and septum with intrinsic rhythm.

The frequency of cases with unaltered TVI waveform in 90 bpm DDD was significantly higher in RV septum than apex.

TVI in DDD (90 bpm)

0

5

10

15

20

Y/Y Y/N N/Y N/N

waveform OK in apex / septum

fre

qu

en

cy (

n)

P = 0.041McNemar's test

TVI in DDD (90 bpm)

0

5

10

15

20

Y/Y Y/N N/Y N/N

waveform OK in apex / septum

fre

qu

en

cy (

n)

P = 0.046McNemar's test

CONCLUSIONS Right ventricular pacing applied in apex or mid-septum

acutely affected both systolic and diastolic function. The QRS duration was longer and the proportion of cases

featuring deep alterations in TVI waveform was higher with apical than septal pacing.

Left ventricular pressure and echocardiographic parameters were similarly affected by RV pacing applied at either site.

Septal stimulation might produce a shorter electrical interventricular delay and milder mechanical modifications in RV with respect to apical pacing, while LV hemodynamic indices dependent on the intraventricular synchronization seem to be less sensitive to the position of the pacing lead.